1. Field of the Invention
The present invention relates to a method and apparatus for providing a timeshift service. More particularly, the present invention relates to a method and apparatus for providing a timeshift service in a digital broadcasting system, and a system thereof.
2. Description of the Related Art
Recently, the growing number of users accessing on-line content over digital broadcasting systems has increased the importance of seamless content delivery. Because of this, adaptive streaming technology has attracted public attention, in which a bit rate of content being delivered is smoothly changed according to the change in the available transmission bandwidth and/or user device performance. This adaptive streaming technology optimizes the bit rate by analyzing the network environments of users. Like the adaptive streaming, content delivery technology, which has been discussed in many standards bodies, selects and plays small segments, which are divided from content based on a Hyper Text Transfer Protocol (HTTP), by user terminals depending on the circumstances, allowing users to seamlessly enjoy the content without delay.
In the Internet Protocol (IP)-based convergence era, convergence of telecommunication and broadcasting is a marketable new business model, which attracts attention as one of the future market-leading technologies. Particularly, Internet Protocol TeleVision (IPTV) is technology that not only provides new services produced by recombining or integrating the existing TV, voice, and data technologies, but also supports interactivities, making it possible to create a variety of business models and services. Unlike the existing service delivery technology specific to the limited terminal environments, the IPTV technology provides services to fixed terminals (e.g., set-top boxes, PCs, and TVs), mobile terminals (e.g., cell phones, and Personal Digital Assistants (PDAs)), wired/wireless networks, and broadcast networks, regardless of the types of terminals and networks, making it possible not only to provide and apply the same services in many different environments, but also to develop various types of services taking various environments into account.
While broadcast content is being played, a user may select and re-view the content having already been played. Generally, this is called a ‘timeshift’ function. It is typical that a device supporting the timeshift function includes a storage device with a specific capacity (e.g., a buffer, a hard disk, and a memory). In this case, however, the timeshift function may be limited to the storage capacity of the storage device. In other words, in the conventional technology, it is not possible to provide the timeshift function to the content having been played earlier than the last stored content of a specific size, and/or to part of the same content. Likewise, the timeshift function may not be provided, even when the content of a specific size is stored in a server or the like on the network, rather than in the device. In the conventional technology, timeshift buffer depth ‘timeShiftBufferDepth’ information is transmitted to a client, using a Multimedia Presentation Description (MPD). A value of the timeShiftBufferDepth represents a period for which a server buffers segments. Conventionally, therefore, after a lapse of ‘representation time’+‘timeShiftBufferDepth’ for each segment, it is not possible to access the related segment.